1. Field of the Invention
Aspects of the present invention relate to an image forming apparatus and a method of using the same.
2. Description of the Related Art
An electro-photographic image forming apparatus uses a fusing process, in which heat and pressure are applied to a printing medium having a transferred toner image, in order to form a high-quality image. Fusing performance is directly affected by a fusing temperature. Typically, when power is supplied, a fusing temperature is increased through a preheating process, and a heating operation of a fusing apparatus is controlled based on the fusing temperature, which is set in accordance with an operational environment (temperature and humidity).
One factor to be taken into consideration when controlling a fusing temperature is how to properly maintain the internal temperature of an apparatus. If a printing medium, heated by passing through a fusing device, is discharged to the outside of the apparatus, heat inside the apparatus is also discharged, and thus the internal temperature may decrease. Accordingly, a printing speed related to the discharge of a printing medium exerts a significant influence upon the internal temperature control of the apparatus.
According to the related art, when the internal temperature of an apparatus becomes high, a printing speed is decreased, such that the internal temperature is properly maintained. If a previously set printing speed is not normal, because the width of a printing medium, set by a user for a printing operation, does not coincide with a width of a printing medium actually used, the internal temperature of an apparatus may increase, resulting in overheating.
In order to solve such a problem, a plurality of temperature sensors are installed at a fusing unit, and the width of a printing medium entering the fusing device is estimated, based on temperature differences detected by the temperature sensors. When a width set by a user (user set width) does not coincide with the width of an actually used printing medium, according to an actual printing medium width detected using a printing medium width sensor, the printing speed may be altered. For example, when the user set width is wider than the width of a non-standardized printing medium that is actually used, the preset printing speed is decreased, such that internal components of an apparatus are protected from excessive heat produced during fusing.
When a printing speed is decreased, while the printing operation is being performed using a non-standardized printing medium, a user who wants a quick printing operation may be dissatisfied. When the amount of printing is not great the apparatus is not overheated, even though a non-standardized printing medium is used. However, if the printing speed is set on the assumption of using the non-standardized printing medium, requirements of users who request a prevention of overheating and a restriction in the decrease of the printing speed, may not be satisfied.
In order to solve such problems, a printing speed of a non-standardized printing medium can be changed, according to the amount of printing in a printing operation. That is, a printing speed is increased in an initial printing operation, and then is decreased when the amount of printing exceeds a preset amount of printing. When such a method is employed, the key point is to set the amount of printing suitable for controlling the printing speed. However, since various printing environments exist, it is difficult to satisfy various users who prefer device stability, by preventing overheating, or who prefer a quicker printing speed.